<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>选择器的权重</title>
    <style>
        *{
            font-size:50px !important;
        }
        div{
            color:green;
            font-size:20px;
        }
        .red{
            color:violet;
        }
        div#box{
            color:blue;
        }
    </style>
</head>
<body>
    <div id="box" class="red">我是一个div
        <span>我是div中的span</span>
    </div>
</body>
</html>